<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style type="text/css">
    * {
        padding: 0;
        margin: 0;
    }

    html,
    body {
        width: 100%;
        height: 100%;
        background: #9CBC2C;
        font-family: "微软雅黑";
    }

    ul,
    ol,
    input {
        list-style: none;
        border: none;
    }

    .main {
        width: 500px;
        margin: 50px auto;
    }

    .main .step {
        padding-left: 43px;
        color: #384313;
        font-size: 16px;
        font-weight: bold;
        text-shadow: 0 1px 1px #c0d576;
        line-height: 40px;
    }

    .main ul li {
        width: 400px;
        height: 25px;
        padding-left: 10px;
        padding-top: 5px;
        padding-bottom: 5px;
        background: rgba(255, 255, 255, .3);
        margin: auto;
        border: solid 2px #e3ebc3;
        border-color: rgba(255, 255, 255, .6);
        border-radius: 5px;
        margin-bottom: 4px;
    }

    .main ul li label {
        font-size: 13px;
        width: 110px;
        color: #111111;
        padding-left: 5px;
    }

    .main ul li input {
        border-radius: 3px;
        border: #FC3 solid 1px;
        width: 250px;
        height: 25px;
        outline: none;
        padding-left: 5px;
        margin-left: 35px;
    }

    .main .savebtn {
        display: block;
        width: 140px;
        height: 40px;
        line-height: 40px;
        text-align: center;
        color: #E3EBC3;
        font-weight: bold;
        cursor: pointer;
        border-radius: 5px;
        margin: 10px auto;
        box-shadow: 1px 1px 1px 0px gray;
        background: linear-gradient(#50B9FD, #1158A8);
    }
</style>

<body>
    <div class="main">
        <span class="step">Step1:用户详细资料</span>
        <ul>
            <li>
                <label>用户名称:</label>
                <input type="text" placeholder="请输入用户名" />
               
            </li>
            <li>
                <label >邮件地址:</label>
                <input type="text" placeholder="example@qq.com" />
            </li>
            <li>
                <label>练习电话:</label>
                <input type="text" placeholder="18566666666" id="demo"/>
            </li>
        </ul>
        <span class="step">Step2:家庭住址（收货地址）</span>
        <ul>
            <li>
                <label>详细地址:</label>
                <input type="text" placeholder="请输入用户名" />
            </li>
            <li>
                <label>邮政编码:</label>
                <input type="text" placeholder="example@qq.com" />
            </li>
            <li>
                <label>国&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;家:</label>
                <input type="text" placeholder="13539008452" />
            </li>
        </ul>
        <span class="savebtn">保存</span>
    </div>
    <script>
        let span = document.querySelector(".savebtn")
        let demo = document.querySelector("#demo")
        let box=document.querySelector("#box")

        span.addEventListener("click", function () {
            if (Number(demo.value) + '' !== NaN +'' ) {
                console.log('是纯数字')
            }else{
                alert("傻逼")
            }
            if(box.value ===""){
                alert("叼毛")
            }
        })

    </script>
</body>


</html>